Bailey Engineering will modify them.
Do yourself a favor and do NOT purchase a parts store re-man ECU. They're junk. The best ECU's are GM originals in good clean condition. A close second are GM re-manufactured and or AC Delco re-manufactured from back in the day when they were still doing them. Any unit you consider purchasing, look closely at the condition of the pins. Make sure there's no corrosion or other damage.
The parts store cardone units are garbage.